Market voices on:

Uber plans to ask Mr Page about a one-on-one meeting with Anthony Levandowski, the engineer at the centre of the legal battle. Mr Levandowski and Mr Page purportedly discussed Mr Levandowski's desire to build self-driving trucks either at Alphabet or by creating his own company, according to a court filing made by Uber.

Mr Levandowski later left Waymo to create Otto, the self-driving trucking company that Uber purchased for US$680 million in stock.

Waymo alleges that Uber stole trade secrets when Mr Levandowski downloaded 14,000 files to his personal computer and then joined Uber to lead the startup's driverless car programme.

Uber fired Mr Levandowski in late May. He has invoked his constitutional right against self-incrimination and has refused to testify in the case, hindering Uber's ability to defend itself against Waymo's claims.

Earlier Friday, Waymo narrowed its case against Uber by dropping three of four patent-infringement claims in the lawsuit.

Travis Kalanick, who resigned as Uber's chief executive officer in June, wanted to meet with Page in March 2015 to discuss a "proper partnership," according to an email Mr Kalanick sent at the time.

But Mr Kalanick said at the time that Mr Page had been "avoiding any meeting with me". Uber also wants to question Mr Page about his work on "side ventures" that may compete directly with Google, the company said.

Mr Page's deposition could help explain the deterioration of the relationship between Uber and Alphabet. The search engine company's venture capital firm is a major investor in Uber and the two companies were once close. In August 2013, Google Ventures, now called GV, invested US$258 million in Uber at a valuation of about US$3.5 billion.

David Drummond, Alphabet's senior vice-president, previously sat on Uber's board. Mr Drummond is also being compelled to submit to a deposition in the case.

"There is no substitute for these depositions, which would resolve some key unanswered questions," an Uber spokesman said in a statement.

"For instance: why, after Google learned of the alleged downloading of 14,000 files, did Mr Page not alert Uber's then-CEO to that fact when they spoke? Simultaneously, Google was rejecting a partnership with Uber, choosing instead to compete."

The case is Waymo LLC v Uber Technologies Inc, 17-cv-00939, US District Court, Northern District of California (San Francisco).